isfinite.3m (2010 09)

i
isfinite(3M) isfinite(3M)
NAME
isfinite( ) - floating-point finiteness macro
SYNOPSIS
#include <math.h>
int isfinite(floating-type x);
DESCRIPTION
The isfinite() macro determines whether its argument has a finite value (zero, denormalized, or nor-
malized, and not infinite or NaN). The argument must be of floating type, and classification is based on
the type of the argument. For HP Integrity servers, the argument can be any floating type. For PA-RISC,
the argument must be either double or float
.
The
isfinite() macro implements the finite() functionality recommended by the IEEE-754 stan-
dard for floating-point arithmetic.
USAGE
To use the
isfinite() macro, compile either with the default
-Ae option or with the -Aa and
-D_HPUX_SOURCE
options. Make sure your program includes <math.h>. Link in the math library by
specifying
-lm on the compiler or linker command line.
RETURN VALUE
The
isfinite() macro returns a nonzero value if and only if its argument has a finite value. The
macro raises no floating-point exceptions.
ERRORS
No errors are defined.
EXAMPLES
Make sure a value is finite before continuing operations on it:
#include <math.h>
/*...*/
float x;
/*...*/
if (isfinite(x))
/*...*/
SEE ALSO
fpclassify(3M), isinf(3M), isnan(3M), isnormal(3M), signbit(3M), math(5).
STANDARDS CONFORMANCE
isfinite(): ISO/IEC C99
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1